Download Mark Scheme - Edexcel

Mark Scheme (Results)
Summer 2016
Pearson Edexcel GCE
in Biology (6BI01) Paper 01
Transport, Genes and Health
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Summer 2016
Publications Code 46640_MS*
All the material in this publication is copyright
© Pearson Education Ltd 2016
General Marking Guidance

All candidates must receive the same treatment. Examiners must mark the first
candidate in exactly the same way as they mark the last.

Mark schemes should be applied positively. Candidates must be rewarded for what they
have shown they can do rather than penalised for omissions.

Examiners should mark according to the mark scheme not according to their perception
of where the grade boundaries may lie.

There is no ceiling on achievement. All marks on the mark scheme should be used
appropriately.

All the marks on the mark scheme are designed to be awarded. Examiners should always
award full marks if deserved, i.e. if the answer matches the mark scheme. Examiners should also
be prepared to award zero marks if the candidate’s response is not worthy of credit according to
the mark scheme.

Where some judgement is required, mark schemes will provide the principles by which
marks will be awarded and exemplification may be limited.

When examiners are in doubt regarding the application of the mark scheme to a
candidate’s response, the team leader must be consulted.

Crossed out work should be marked UNLESS the candidate has replaced it with an
alternative response.
Question
Number
1(a)(i)
Answer
Additional Guidance
C
Question
Number
1(a)(ii)
(1)
Answer
Additional Guidance
B
Question
Number
1(a)(iii)
Question
Number
1(b)(ii)
Answer
Additional Guidance
Mark
(1)
Answer
Additional Guidance
8
Mark
(1)
Answer
6
Mark
(1)
C
Question
Number
1(b)(i)
Mark
Additional Guidance
Mark
(1)
Question
Number
1(c)
Answer
Additional Guidance
1. DNA is {double stranded/ has a double helix} and RNA is
{single stranded / does not have a double helix} ;
1. ACCEPT mixtures e.g. DNA double
helix mRNA is single strand
IGNORE hydrogen bonds
2. DNA has {thymine / T } while RNA has { uracil / U } ;
2.NOT thiamine, thyamine
Mark
3. DNA has deoxyribose while RNA has ribose ;
4. DNA is { larger / longer } than RNA / eq ;
(3)
Question
Number
2(a)
Question
Number
2(b)
Answer
Additional Guidance
Mark
correct answer only gains both marks
1. 32.2 – 7.6 = 24.6 ;
ACCEPT 7.6 ÷ 32.2
2. (÷ 32.2) × 100 = 76.4 / 76. 40 ;
100 – 23.6 = 76.4 / 76.40
Answer
Additional Guidance
(2)
Mark
1. idea of producing liquid extract of cabbage;
2. description of titration ;
2. e.g. set volume of extract and find
the volume of DCPIP needed or
converse
3. reference to use of DCPIP ;
4. correct colour change described ;
4. e.g. it goes colourless when extract
added, add DCPIP until it goes blue
5. compare volumes with standard e.g. reference to use of
calibration curve / eq ;
6. description of appropriate standardisation of extract e.g.
mass of cabbage, volume of liquid added to cabbage ;
(4)
Question
Number
2(c)(i)
Answer
Additional Guidance
Mark
1. cell membranes {damaged / permeable / eq} ;
2. vitamin C leaves the {cells / cabbage} (because it is
water soluble) ;
3. vitamin C is destroyed by {boiling / enzyme / ascorbic
acid oxidase } ;
Question
Number
2(c)(ii)
Question
Number
2(d)
Answer
the { enzyme / ascorbic acid oxidase } would have been
denatured (quicker when added to the boiling water) ;
Answer
(2)
Additional Guidance
ACCEPT for cold water: enzyme is
more active as water is heated up or
vitamin C leaks out as it heats up
Additional Guidance
Mark
(1)
Mark
1. idea that stored sauerkraut still contains some vitamin
C.
2. cabbage would {rot / decompose / eq } ;
ACCEPT sauerkraut does not rot
(1)
Question
Number
3(a)(i)
Answer
Additional Guidance
Mark
IGNORE 50% are affected
1. idea of it being frequently inherited in the family e.g. 1,
7 and 10 all have affected offspring, 9 of the family
have the disorder ;
1 ACCEPT 8 of 14 descendants of 1
and 2
2. individual { 1 / 3 / 7 / 10 } must be heterzygous / eq ;
2 ACCEPT have one dominant allele
3. use of the pedigree diagram to explain mark point 2 ;
4. appropriate use recessive allele argument e.g. if it were
recessive then 2 would have to be {heterozygous / a
carrier} ;
5. idea that it is unlikely that the unrelated parents
{ 8 / 11 } would also be carriers of the affected allele ;
(3)
Question
Number
3(a)(ii)
Answer
1. parents gametes displayed correctly ( e.g. M, m and m
,m) ;
Additional Guidance
Mark
1. ACCEPT gametes shown on a
punnett square alone
2. correct genotypes of offspring shown ;
3. probability matches genotypes shown e.g. 0.5 / ½ / 1 in
2 / 50% ;
3. ACCEPT other probabilities if
match genotypes shown
(3)
Question
Number
3(b)
Answer
Additional Guidance
Mark
Any two pairs from:
1. idea that there is a { thick wall / thick layers / thick
tunica media / eq } ;
2. idea that it needs to { avoid rupture / withstand high
pressure / allow expansion / eq } ;
3. collagen / elastic fibres ;
4. allow expansion / elastic recoil ;
5. muscle { layer / fibres / wall / eq } ;
3 and 4 . ACCEPT folded
{endothelium / (inner) surface} allows
expansion
6. control the flow of blood / maintain blood pressure / eq ;
7. smooth endothelial wall / eq ;
8. to reduce { friction / resistance / eq } ;
9. narrow lumen ;
10.(to maintain) high blood pressure / eq ;
(4)
Question
Number
4(a)(i)
Question
Number
4(a)(ii)
Answer
Additional Guidance
B (are R and S) ;
Mark
(1)
Answer
Additional Guidance
C (is P only) ;
Question
Number
4(b)
Mark
(1)
Answer
Additional Guidance
Mark
1. glycerol plus three fatty acids as reactants ;
2. ester bond labelled ;
2 ACCEPT an ester bond drawn out
correctly even if not labelled
3. water shown ;
(3)
Question
Number
4(c)(i)
Question
Number
4(c)(ii)
Answer
condensation / polymerisation ;
Answer
glycosidic / 1,4 glycosidic ;
Additional Guidance
Mark
ACCEPT polymerization
(1)
Additional Guidance
ACCEPT glycoside
ACCEPT missing commas and
commas replaced with dashes
NOT 1,6 glycosidic
IGNORE link or bond
Mark
(1)
Question
Number
4(c)(iii)
Answer
Additional Guidance
Amylose is {coiled / unbranched / eq } / amylose has only 1,4
(glycosidic) bonds / eq ;
ACCEPT glycogen is not coiled /
branched / has 1,4 and 1,6 glycosidic
bonds
Answer
Additional Guidance
Question
Number
4(c)(iv)
1. contain glucose / eq ;
2. idea that they are compact so large {numbers of
glucose / amylose / glycogen } molecules can fit into a
small volume ;
3. insoluble therefore {does not affect osmosis / eq } ;
4. large molecules therefore { remains in cells / too big to
diffuse / eq} ;
Mark
(1)
Mark
ACCEPT if each described
separately but allow each Mp
once only
1. ACCEPT can be hydrolysed /
broken down to release glucose
2. ACCEPT large amounts of energy
in a small volume
3. IGNORE insoluble so will not
dissolve
(2)
Question
Number
5(a)
Answer
Additional Guidance
NB any sign of an arrow then item
to go to review.
1. platelets ;
1. ACCEPT plattelets, platellets
2. prothrombin ;
2. ACCEPT prothrombrin
3. fibrin ;
Question
Number
5(b)
Mark
(3)
Answer
1. prevents oxygen reaching the heart {muscle / cells /
tissue / eq} ;
2. prevents (aerobic) respiration ;
3. (cardiac) muscle { unable to contract / dies / eq } ;
Additional Guidance
Mark
1. ACCEPT heart muscle ischaemic
2. ACCEPT reference to anaerobic
respiration / lactic acid production
ACCEPT { no / less } ATP is
produced
3. ACCEPT produces interference in
the electrical impulses across the
heart / eq
ACCEPT cells of the heart die
(3)
Question
Number
5(c)(i)
Answer
Additional Guidance
Mark
1. description of the trend e.g. increasing ratio decreases
death rate, negative correlation / eq ;
2. highest death rate in countries with lowest ratio of
unsaturated to saturated fatty acids / eq ;
2. ACCEPT converse
3. correct manipulation of figures to illustrate relationship ;
3. e. g. Finland and Italy 2x ratio /
deaths down by 268
Finland and USA ratio up by 0.1
/ deaths down by 95
(3)
Question
Number
5(c)(ii)
Answer
1. increase the ratio of unsaturated to saturated in their diet /
eq ;
Additional Guidance
Mark
1.ACCEPT eat more unsaturated and
less saturated
2. because in countries with a low ratio of unsaturated to
saturated the death rate by CVD is high / eq ;
3. replace animal fats with plant oils / reduce animal fats /
increase plant oils ;
3. ACCEPT suitable reference to beef,
butter, olive oil and corn oil
4. because {animal fats / beef / butter } have a high % of {
saturated fatty / palmitic / stearic } acids /
OR
{ plant oils / olive and corn oil } have a high % of
{unsaturated fatty / linoleic / oleic } acids
OR
{ saturated fatty / palmitic / stearic } acids raise blood
cholesterol /
OR
{ unsaturated fatty / linoleic / oleic } acids {reduce / do
not raise } blood cholesterol (to reduce chance of death)
;
(3)
Question
Number
5(d)
Answer
Additional Guidance
Mark
1. other { variables / uncontrolled variables / eq } affect
CVD ;
2. genetic differences (between national populations) / eq
;
3. (countries have) {environmental / life style }
differences / eq ;
4. idea that data does not provide a causal { link /
mechanism} ;
2. ACCEPT gender
3. ACCEPT differences in levels of
activity, smoking, other dietary
factors e.g. salt, alcohol consumption
ACCEPT age profiles of countries
may differ
(2)
Question
Number
6(a)(i)
Answer
Additional Guidance
Mark
D – passive transport
(1)
Question
Number
6(a)(ii)
Answer
Additional Guidance
Mark
C - ions move down a concentration gradient
(1)
Question
Number
6(a)(iii)
Answer
Additional Guidance
Mark
B - involves the production of a vacuole or vesicle
(1)
Question
Number
6(b)(i)
Answer
1. idea that the rate of uptake {is constant for first 5
minutes / reduces after 5 minutes} ;
Additional Guidance
Mark
1. ACCEPT idea of linear increase in
first 5 minutes
2. idea that { concentration of W reaches a maximum /
no more uptake / stays at 0.6 mol dm-3 } from 10
minutes ;
3. suitable manipulation of figures e.g. rate of uptake in
first 5 minutes is 0.1 moldm-3 per minute ;
(3)
Question
Number
6(b)(ii)
Answer
Additional Guidance
Mark
1. uptake {slows down / is less / stops} / eq ;
2. because of smaller {concentration / diffusion }
gradient / eq ;
2 ACCEPT converse
3. credit argument for why it is not another process e.g.
not osmosis as the solute concentration rises from 0,
not active transport as it will continue to rise and not
reach a maximum ;
(2)
Question
Number
6(c)
Answer
Additional Guidance
Mark
1. idea that water has moved into the cell ;
2. by osmosis ;
3. idea of a solute concentration gradient ;
3. ACCEPT water {potential /
concentration} gradient
4. cell membrane ruptures / eq ;
(3)
Question
Number
7(a)(i)
Answer
Additional Guidance
Mark
Blood vessel at bottom of diagram with blood flowing away
from the capillaries clearly labelled {P / pulmonary vein};
(1)
Question
Number
7(a)(ii)
Answer
Additional Guidance
Any one difference described e.g.
1. capillary wall is one cell thick while vein wall is thicker /
eq
2. capillary has no {collagen/ muscle}
1. ACCEPT capillary wall is only one
cell thick
NOT cell wall
2 ACCEPT converse
3. capillaries do not have valves
3 ACCEPT converse
4. smaller lumen in capillaries than veins ;
Question
Number
7(b)
Mark
Answer
(1)
Additional Guidance
Mark
1. O2 diffuses more quickly than CO2 ;
2. different concentration gradients / eq ;
3. molecules are different sizes / eq ;
2. ACCEPT higher concentration
gradient for O2.
ACCEPT gradients are 7 for oxygen
and 2 for carbon dioxide
(2)
Question
Number
7(c)
Answer
(QWC – Spelling of technical terms must be correct and
the answer must be organised in a logical sequence)
1. idea that large surface area provided by alveoli ;
2. idea that large surface area provided by capillary network ;
Additional Guidance
Mark
QWC emphasis is on clarity of
expression
1&2. IGNORE large surface area to
volume ratio unless in context of
whole body
3. idea that concentration gradient maintained by {ventilation
of / air flow in / eq } the lungs ;
4. idea that concentration gradient maintained by {circulation
/ mass flow / eq } of blood ;
5. idea that diffusion pathway is small because alveoli
have a thin wall ;
5.& 6. NOT cell wall
6. idea that diffusion pathway is small because capillaries
{ have a thin wall / are in contact with alveoli / are
only one cell thick / eq } ;
7. idea that air is warmed because lungs are in core of
body ;
8. warmer air enables faster {movement / diffusion / eq }
of gases / eq ;
9. reference to { respiratory pigment / haemoglobin / red
blood cells / eq } to carry oxygen ;
(5)
Question
Number
8(a)(i)
Answer
Additional Guidance
Mark
1. life expectancy is likely to be lower than {Aa /
heterozygote} ;
2. because of higher chance of (developing) malaria / eq ;
OR
3. life expectancy may be {higher / same } than {aa /
homozygous recessive} ;
4. because of {less / similar} severity of anaemia ;
Question
Number
8(a)(ii)
Answer
(2)
Additional Guidance
Mark
1. idea they (heterozygotes) are less likely to have { malaria /
anaemia } ;
2. idea that { Plasmodium / parasite / eq } unable to
reproduce (and cause wider infection)
OR
lower (functional) red blood cell count / blocking of blood
vessels causes {pain / cell death / eq} ;
2 ACCEPT parasite will die
(2)
Question
Number
8(b)
Answer
Additional Guidance
(QWC – Spelling of technical terms must be correct and
the answer must be organised in a logical sequence)
QWC emphasis is on logical
sequence
Maximum of 3 from Mps 1 to 4
1. reference to change in primary structure ;
1. IGNORE sequence of amino acids
Mark
2. reference to different R group ;
3. leading to different named bond e.g. ionic, hydrogen,
disulfide ;
3. ACCEPT type or position of bonds
IGNORE peptide
4. different { folding / secondary / tertiary / 3D structure /
globular } ;
5. suggested change in properties of the haemoglobin e.g.
change in solubility, flexibility, affinity for oxygen / eq ;
5. ACCEPT {less/no} oxygen will bind
to haemoglobin
(4)
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